Heat exchanger

[Chas]

Have you got the translation Chris? I couldn't understand a word he said.

 

[Chris]

French I think Chas.

Stu, only thinking out loud. I have a company car for when it's cold and I need to go out early. It was just an idea. Just like the heated washer bottle project..
What is clear is there is tonnes of free heat here. The only bit that you really need a proper bought bit for is the exchanger. I like the free heater one as is flat and easily mounted inn the vehicle. Don't need the rear heater. Pipes are there. Could have a cold water pick up coiled under the seat too to drop straight into a container filled from the river to preserve drinking water supply.

 

[clivehorridge]

It all makes sense to me now, sorry to be a little slow!

All very neat and reasonably cheap. I think you guys (even me) could make a heat exchanger out of copper tubing that would work just as well. Whether it would be cheaper than a bought one is debatable. Like it!

 

[Chris]

Clive I think there is voodoo magic inside there. I'll bet it's platinum infused unicorn eyelashes or something. It transfers the heat very efficiently. Some old barrel strapped to the roof with heating pipes dunked in there probably won't cut it

 

[clivehorridge]

Clive I think there is voodoo magic inside there. I'll bet it's platinum infused unicorn eyelashes or something. It transfers the heat very efficiently. Some old barrel strapped to the roof with heating pipes dunked in there probably won't cut it

Unless you slice it, you'll never know But TBH I'd be surprised if it's nothing more than some copper fins at the most. Maybe I'll give one a go and see what happens. Of course, you'll only get to know about it if it's a success

 

[grantw]

Clive - loads of good information and sketches on wikipedia if you're going to make one from scratch.

 

[karl webster]

Nice thread.

i made a heat exchanger for my cooking oil conversation Clive work well. As far as the cooking oild exchangers go I know they are fairly complex inside as Chris was saying they have plenty of fins inside where the oil goes through. Plenty of surface area for the fluids to heat up.
Quite like Chris' idea using the rear heater pipes. Block heater would be my way forward as well. For me I could have the truck warm every morning before I've even got into it.

 

[clivehorridge]

Clive - loads of good information and sketches on wikipedia if you're going to make one from scratch.

Thanks Grant, I'll check this out. It'll give me a pottering job in the shed if nothing else!

 

[clivehorridge]

Interesting read on wiki, but the most informative bit was that U=Q/AΔTlm....

Just what I needed to know.... Now, where's my shed keys?

 

[stumog]

the commercal heat exchangers i have come across have been made of lots of aluminium plates with ridges stamped in them so when you have one on top of the other they touch. rubber seal on each as well. very straight forwad. these seem to be the same constrution.
stu

 

[Chris]

For those of you who are desperately interested, I warmed the truck up today, kept the slider on cold. No front fans running, the back heater threw out cold air. I don't think this is going to surprise anyone by the way. Then I moved the slider to hot and after a few seconds the air became warm. Now I have to say I am still not staggered by the heat coming out of my heater in the front. It's OK but it doesn't exactly dry your eyeballs and take a very long time to heat up. Anyway. I felt the pipes underneath coming in the heater and they were certainly hotter than you'd want water to be for showering.

So conclusion is that you can have heater on cold, pull up, slide the slider and pump water round the engine and rear heater pipes into an exchanger. Doesn't save you a fortune, but it eliminates one more piece of plumbing and makes use of the space under the seat. I reckon with the fan unit removed you could fit a small bar of soap, a sponge and a shower cap in there too. Double result.

I think I shall measure up and get on with this. If it doesn't work then I can go to plan B. Or as the current wife likes to call it, a hotel.

 

[adrianr]

Plan b made me chuckle.

I reckon your plan is sound mate. Good luck.

 

[clivehorridge]

Plan b made me chuckle.

I reckon your plan is sound mate. Good luck.

Plan B made me laugh too! I ran the same check and yes the temperature slider controls both front and back heaters the same.

I still think a heat exchanger could be made, I'm working on some simple ideas...

 

[Himesed]

Anybody know how does a isomer heat exchanger works?

 

[SteveS]

French I think Chas.

Stu, only thinking out loud. I have a company car for when it's cold and I need to go out early. It was just an idea. Just like the heated washer bottle project..
What is clear is there is tonnes of free heat here. The only bit that you really need a proper bought bit for is the exchanger. I like the free heater one as is flat and easily mounted inn the vehicle. Don't need the rear heater. Pipes are there. Could have a cold water pick up coiled under the seat too to drop straight into a container filled from the river to preserve drinking water supply.

Chris - did you implement your under the seat connections - I've gone through the same logic on my "Hedgehog" 100 overland build thread and come to similar conclusions that it looks a neat way of connecting up a shower heat exchanger. The 100 may be a bit more 'complex' potentially in terms of heating controls/automation - I don't know - but it would be good to get your experiences on that one

 

[Chris]

Yes mate I did. it gives me nice hot water. We've actually used it to shower the dog. One thing though, I find that the engine doesn't stay that warm for that long. The video for the product shows Debbie having a lovely shower some time after the engine had run. If I pull up, I reckon I only have 30 - 40 mins to use that heat before it's cooling off. I am probably losing quite a bit of heat in the pipes but not much I can do. I don't know if I am pushing enough of the water around the engine with the pump. I have wondered about putting a bigger pump in the top hose off the rad. Anyway, yes the system works and gives good hot water. My cold water supply goes round the same system - just the temp slider set to cold or the engine is already cold. I am looking at fitting a Y diverter so I can have cold straight from the tank out of the same tap. Just not found the parts yet.

I could move the HE unit to the bonnet and also run cold in from the back but take hot out from under the bonnet too. This would cut down on the travel of hot water, but I don't really want to have water at the opposite end of the truck when I need it really.

 

[SteveS]

Yes mate I did. it gives me nice hot water. We've actually used it to shower the dog. One thing though, I find that the engine doesn't stay that warm for that long. The video for the product shows Debbie having a lovely shower some time after the engine had run. If I pull up, I reckon I only have 30 - 40 mins to use that heat before it's cooling off. I am probably losing quite a bit of heat in the pipes but not much I can do. I don't know if I am pushing enough of the water around the engine with the pump. I have wondered about putting a bigger pump in the top hose off the rad. Anyway, yes the system works and gives good hot water. My cold water supply goes round the same system - just the temp slider set to cold or the engine is already cold. I am looking at fitting a Y diverter so I can have cold straight from the tank out of the same tap. Just not found the parts yet.

I could move the HE unit to the bonnet and also run cold in from the back but take hot out from under the bonnet too. This would cut down on the travel of hot water, but I don't really want to have water at the opposite end of the truck when I need it really.

Thanks Chris - I'm planning on having the engine running for showering and either playing with the temp controls OR putting in a manual flow restrictor to reduce the flow of hot water when I'm showering (if too much heat is a problem). Potentially I could experiment with having the shower heat exchanger in parallel across the heater matrix and having some manual valves.....

Your 80 may be different from my 100 but did your rear heater matrix metal pipe terminals go through the floor and connect to rubber pipes on the outside OR did rubber pipes come through the floor?

In terms of water not being hot enough have you thought about putting the water round the heat exchanger twice? it only works if there is sufficient heat in the engine but would help to overcome conversion efficiency/losses or very cold input water. People use a bucket and suck the water back into the system for a second time.

 

[Chris]

Now you are asking me. Errm, metal pipes under the floor then into flexi and then metal pipes from the heater went through the floor to join the flexi

I didn't say the water wasn't hot enough Steve. On full, it's perfect. What I meant was that the engine doesn't seem to stay hot that long. If I tried to run hot water an hour after stopping, it would not be hot. But the set up in the video add showed it to be scorching from a normal car engine. We know that tyoically the 80 engine doesn't suffer from poor cooling. Maybe it's that good that when parked it cools very quickly.

 

[SteveS]

Chris - I asked Tim over in Oz who runs the Glind operation on his thoughts on using the rear heater pipes...response below

Hello Steve,
I have heard about this before and the people who used it had troublegetting heat from the back heater.
This was because the coolant was tee’d off and as a result, half thecoolant was going to the back heater and half to the front, enough to warm theinside cabin, but not enough to run a heat exchanger sufficiently.
I would stick with the setup I have emailed you as this works well.
Regards,
Tim

 

[SteveS]

I didn't say the water wasn't hot enough Steve. On full, it's perfect. What I meant was that the engine doesn't seem to stay hot that long. If I tried to run hot water an hour after stopping, it would not be hot. But the set up in the video add showed it to be scorching from a normal car engine. We know that tyoically the 80 engine doesn't suffer from poor cooling. Maybe it's that good that when parked it cools very quickly.

Yes I understood that.....so if after an hour your engine has cooled then you may wish to pass the water twice around the system just to get the most out of the heat that you do have left in the engine